ASCO Breast Reports on Recurrence after Early Chemotherapy
Among the studies discussed on September 4 at the American Society of Clinical Oncology 2014 Breast Cancer Symposium was an analysis of breast cancer recurrence rates after pre-surgery, or neoadjuvant, chemotherapy.
Because there is limited information on local and regional recurrence rates in people treated with neoadjuvant chemotherapy, doctors have disagreed on when to use sentinel lymph node biopsy and radiation therapy after surgery. Local recurrence is cancer that returns at or near the place as the original tumor; regional recurrence is cancer that comes back in nearby lymph nodes or nearby organs or tissues.
Findings from a review of 12 large clinical trials on neoadjuvant chemotherapy, the largest study of its kind to date, were presented Thursday by Eleftherios P. Mamounas, MD, professor at the University of Central Florida College of Medicine.
His team found that local and regional recurrence rates after neoadjuvant chemotherapy are low—below 10 percent at five years. Breast cancer subtype and whether there was pathologic complete response (pCR), meaning cancer cannot be found after pre-surgery chemotherapy, were the strongest factors that allowed researchers to predict the chance of recurrence. Cancer stage and whether or not cancer was found in the lymph nodes were also factors.
Neoadjuvant and adjuvant (post-surgery) chemotherapy provide equal survival benefits, but more people typically have adjuvant therapy. An advantage of receiving chemotherapy before surgery is that it can shrink and sometimes eliminate the tumor in the breast and lymph nodes in the armpit region, possibly reducing the need for mastectomy, lymph node removal and radiation therapy after surgery.
Researchers analyzed local and regional recurrence rates in 11,955 participants who received neoadjuvant chemotherapy. About half of participants were under age 50, and most had stage II or stage III breast cancer—very few had stage I disease. Most participants who had lumpectomy also had radiation therapy after surgery.
Their main goal was to measure local and regional recurrence rates by pCR, tumor subtype and surgery type, among other factors.
After a median follow-up period of 5.4 years, local and regional recurrence rates were 8.3 percent overall. Although age, tumor subtype, cancer stage and pCR status were all predictors, factors that allowed the team to predict the chance of recurrence, the study shows that pCR and tumor subtype may be more informative than the tumor stage at diagnosis (which is commonly used in current practice) for evaluating local and regional recurrence risk.
People whose cancers did not have a pathologic complete response to neoadjuvant chemotherapy had a greater risk of local and regional recurrence. Those with cancer cells left in the breast and no cancer in the lymph nodes around the armpit had 1.6 times higher risk, and those with cancer cells left in the breast as well as cancer in the lymph nodes around the armpit had 2.8 times higher risk.
People with HER2-postive, hormone receptor-negative breast cancer were more likely to have a recurrence (14.8 percent), as well as those with triple-negative disease (12.2 percent). For those who had a lumpectomy, the strongest predictor of recurrence was breast cancer subtype; the strongest predictor of recurrence for those who had a mastectomy was pCR status.
Dr. Mamounas said it is important to note that only one-third of participants with HER2-positive breast cancer received trastuzumab (Herceptin) after surgery. Today, almost all would receive it.
Researchers also found that more advanced stage at diagnosis did not negatively affect rates of local and regional recurrence when pCR and tumor subtype information were taken into account.
What This Means For You
Results of this and other studies clearly suggest that people who have HER2-positive, triple-negative or fast-growing ER-positive disease but whose cancers achieve pCR are less likely to have a breast cancer recurrence than those who do not.
Although more research is needed to inform new practice guidelines, these findings provide more information for you and your doctor to consider when trying to decide on the best treatment options after neoadjuvant chemotherapy, including whether or not you may benefit from adjuvant radiation therapy. Talk with your doctor about whether neoadjuvant chemotherapy may a good option for treating your breast cancer and preventing nearby recurrences.